I'm using an Amplex Red kit, the reagent changes color to pink almost immediately in my own Krebs-Ringer buffer but not in HBSS. Why is this?
The components of Krebs-Ringer buffer (salts) should not cause oxidation of the Amplex reagent (which, in the presence of peroxidase and H2O2 oxidizes to resorufin, which is pink in color and fluorescent). Try water alone (the water used to make the Krebs-Ringer buffer). Since Hank's Buffered Saline Solution is typically purchased rather than made in the lab, it likely would not have the same contaminant. Another option is to degas the buffer prior to use to removed dissolved oxygen radicals.
Can Amplex Red Assays be performed using cell lysates?
This is not recommended. The presence of endogenous proteases can complicate the assay by degrading the horseradish peroxidase (HRP). Endogenous peroxidases and antioxidants can modify the H2O2 required for the reaction, competing with HRP (and catalase) for the substrate.
The Amplex Red Assays are best performed with either purified enzymes or extracted H2O2 in a defined buffer system, extracellular solutions or body fluids (media, serum, etc.) that do not exhibit high levels of endogenous protease or oxidase activity and do not contain antioxidants.
Involvement of the acid sphingomyelinase pathway in uva-induced apoptosis.
Authors:Zhang Y, Mattjus P, Schmid PC, Dong Z, Zhong S, Ma WY, Brown RE, Bode AM, Schmid HH, Dong Z
Journal:J Biol Chem
PubMed ID:11278294
'The sphingomyelin-ceramide pathway is an evolutionarily conserved ubiquitous signal transduction system that regulates many cell functions including apoptosis. Sphingomyelin (SM) is hydrolyzed to ceramide by different sphingomyelinases. Ceramide serves as a second messenger in mediating cellular effects of cytokines and stress. In this study, we find that acid sphingomyelinase (SMase) ... More
Combination brain and systemic injections of AAV provide maximal functional and survival benefits in the Niemann-Pick mouse.
Authors:Passini MA, Bu J, Fidler JA, Ziegler RJ, Foley JW, Dodge JC, Yang WW, Clarke J, Taksir TV, Griffiths DA, Zhao MA, O'Riordan CR, Schuchman EH, Shihabuddin LS, Cheng SH
Journal:Proc Natl Acad Sci U S A
PubMed ID:17517638
'Niemann-Pick disease (NPD) is caused by the loss of acid sphingomyelinase (ASM) activity, which results in widespread accumulation of undegraded lipids in cells of the viscera and CNS. In this study, we tested the effect of combination brain and systemic injections of recombinant adeno-associated viral vectors encoding human ASM (hASM) ... More
Protection from high fat diet-induced increase in ceramide in mice lacking plasminogen activator inhibitor 1.
Authors:Shah C, Yang G, Lee I, Bielawski J, Hannun YA, Samad F,
Journal:J Biol Chem
PubMed ID:18359942
'Obesity increases the risk for metabolic and cardiovascular disease, and adipose tissue plays a central role in this process. Ceramide, the key intermediate of sphingolipid metabolism, also contributes to obesity-related disorders. We show that a high fat diet increased ceramide levels in the adipose tissues and plasma in C57BL/6J mice ... More
Counteracting suppression of CFTR and voltage-gated K+ channels by a bacterial pathogenic factor with the natural product tannic acid.
Authors:Ramu Y, Xu Y, Shin HG, Lu Z,
Journal:
PubMed ID:25313718
'Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) cause recurring bacterial infection in CF patients'' lungs. However, the severity of CF lung disease correlates poorly with genotype. Antibiotic treatment helps dramatically prolong patients'' life. The lung disease generally determines prognosis and causes most morbidity and mortality; early control of ... More
Ceramide upregulation causes pulmonary cell apoptosis and emphysema-like disease in mice.
Authors:Petrache I, Natarajan V, Zhen L, Medler TR, Richter AT, Cho C, Hubbard WC, Berdyshev EV, Tuder RM
Journal:Nat Med
PubMed ID:15852018
'Alveolar cell apoptosis is involved in the pathogenesis of emphysema, a prevalent disease primarily caused by cigarette smoking. We report that ceramide, a second messenger lipid, is a crucial mediator of alveolar destruction in emphysema. Inhibition of enzymes controlling de novo ceramide synthesis prevented alveolar cell apoptosis, oxidative stress and ... More